Asynchronous H_∞ Continuous Stabilization of Mode-Dependent Switched Mobile Robot

Four-wheeled steerable mobile robots have been widely used in industrial fields. However, robust tracking control is hard to achieve with a fixed maneuver mode. Based on a novel internal coupled sliding mode control (ICSMC) method, this study handles the above challenge by constructing a mode-dependent switched mobile robot (MSMR), and then designing an asynchronous H∞ continuous stabilization control scheme. This method governs the system behaviors to perform adaptive-mode allocations asynchronously and smoothly. First, a unified expression of MSMR is formulated, which regards the maneuver modes as optional subsystems. Then, with the coupled sliding surfaces and modified reaching law, an enhanced chattering-free ICSMC technique is established to optimize continuous control inputs for each subsystem. Moreover, using a surveillant criterion that depicts the energy decaying rate, an evaluation rule is built to distinguish the mismatched subsystems and then realize autonomous mode switching for the concerned MSMR. Utilizing piecewise Lyapunov functional technique and mode-dependent average dwell time, new sufficient conditions are derived for global exponential stability and H∞ performance. Comparative experiments implemented on the developed MSMR are carried out to verify the effectiveness of the proposed control scheme.